package com.rd.student.jiaji.class1.wangyufang.day0731;

import java.util.HashSet;

public class TestRandom1 {
    public static void main(String[] args) {
        HashSet<Integer> set = new HashSet<>();
        while(set.size()<20){
            int n = (int)(Math.random()*50);
            set.add(n);
        }
        System.out.println(set);
    }
}
